It is the purpose of this project to: 1) improve upon current methods of isolation of islets of Langerhans, 2) determine new methods of preservation through: a) perifusion of the islets, b) tissue culture and c) cryopreservation techniques, and 3) develop an optimal site for transplantation of islets into selected human diabetic recipients. Improvement of the basic techniques of isolation, preservation, and transplantation will be developed using rat tissue. Concomitantly, human tissue will be utilized in the study of isolation and preservation. Once the results of transplantation have proven conclusively to be effective in the rat, and once isolation and short term preservation techniques for human tissue have been perfected, transplantation of pancreatic islets will proceed in diabetic recipients. Insulin-requiring adult diabetics well advanced in their disease will be utilized initially for subcutaneous transplantation. If it proves effective in the adult, then transplantation will be considered for the juvenile group as a possible treatment for diabetes mellitus.